A railway network is made up of various elementary objects, such as a track section with two end points, a track section with three end points or coupled switches, a signaling element, etc.
At a given moment, each object is in an interlocking state assuming a specific value among a plurality of predefined possible values.
To date, an interlocking logic is used to authorize a vehicle to move safely along a route of the railway. The interlocking logic is implemented by centralizing equipment, hereinafter called control unit, which controls the interlocking state of all of the elements composing the network.
The interlocking logic uses a route table that shows, for each possible route, the values of the interlocking states of the objects composing said route that must be simultaneously verified to authorize the vehicle to move safely on the considered route. The definition of the route table is a compromise between flexibility and operating possibilities, technical feasibility and cost, while also considering deadlocks between movements.
It is the control unit that, each moment, selects a route for a vehicle, modifies the interlocking state of the objects composing that route in compliance with the conditions mentioned in the route table, then, after verifying compliance with those conditions, authorizes the vehicle to move on the route.
The control unit thus manages the movement of all of the vehicles circulating, at any given moment, on the railway network.
The complexity of the route tables and the need for them to guarantee safe movements on the railway network that they describe, require that the route tables be generated manually, by experts. As a result, the creation of the route tables is a very costly step in terms of resources.
Lastly, this architecture does not permit to update easily an existing railway network. For example, the replacement or addition of an object must be followed by the rewriting of the route table and its qualification before it can be integrated at the control unit.